This application is based upon and claims priority of Japanese Patent Applications No. 2000-333228, filed on Oct. 31, 2000, the contents being incorporated herein by reference.
1. Field of the Invention
The present invention relates to an electronic musical instrument and tone volume control method and, more particularly, to a technique which is suitably used in an electronic musical instrument for correcting a tone signal in accordance with given frequency characteristics in correspondence with the tone volume of a tone to be generated, and generating the tone.
2. Description of the Related Art
A conventional electronic musical instrument such as an electronic organ, electronic keyboard, and the like comprises a volume switch for setting a tone volume, and an expression pedal (to be referred to as an xe2x80x9cEXP pedalxe2x80x9d hereinafter) for inflecting tones by controlling the tone volume during a performance. The electronic musical instrument controls the volume of tones to be generated in accordance with the operations of the volume switch and EXP pedal. Also, an electronic musical instrument which has an external interface such as a MIDI (Musical Instrument Digital Interface) or the like controls the volume of tones to be generated on the basis of supplied automatic performance data such as MIDI data or the like.
The volume of tones generated by the electronic musical instrument is controlled by changing the volume of all tones generated in accordance with the operation state of the volume switch or EXP pedal without changing the electric frequency characteristics. That is, the volume of tones generated is controlled by changing all frequency components of tone signals of tones generated by the electronic musical instrument by the same amount.
However, as is generally known as equal loudness contours (Fletcher-Munson contours), the human ear has different hearing frequency characteristics (to be referred to as xe2x80x9chearing characteristicsxe2x80x9d hereinafter) depending on the tone volume. The human ear is highly sensitive to tones within the range of around 1 to 4 kHz but is less sensitive to tones having frequencies lower than this range (bass) and higher than that range (treble). Especially, it becomes harder for the human ear to hear bass tones with decreasing tone volume.
For this reason, in the aforementioned tone volume control of the electronic musical instrument, bass and treble tones of tone signals, which are optimal at a certain tone volume, become harder to hear by decreasing the tone volume, and midrange tones around 1 to 4 kHz are conspicuously easy to hear. For example, in tones containing a bass tone color, those of the bass tone color becomes harder to hear by decreasing the tone volume.
In the conventional tone volume control of the electronic musical instrument, when the volume of tones to be generated is changed, the balance among tone colors of tones to be generated by the electronic musical instrument, and the tone colors themselves sound differently depending on the hearing characteristics.
The present invention has been made to solve the aforementioned problems, and has as its object to maintain tone volume balance among tone colors of tones to be generated by an electronic musical instrument, and the tone colors themselves upon hearing independently of the tone volume of tones to be generated.
An electronic musical instrument of the present invention is an electronic musical instrument for generating a tone on the basis of a tone signal, comprising a filter having hearing correction characteristics for correcting the received tone signal, and a mixing unit for mixing the received tone signal and the tone signal, which is corrected by the filter, at a given ratio on the basis of tone volume control information used to control a tone volume of the tone to be generated, and outputting the mixed signal.
According to another feature of the present invention, the mixing unit comprises a balance adjustment unit for adjusting, on the basis of the coefficient, a tone volume balance of tones to be generated based on the received tone signal and the tone signal corrected by the filter, and a tone volume adjustment unit for adjusting, on the basis of the coefficient, the tone volume of tones to be generated based on the received tone signal and the tone signal corrected by the filter.
A tone volume control method of the present invention is a tone volume control method of controlling a tone volume of a tone to be generated based on a tone signal, comprising the step of correcting the received tone signal by a filter having hearing correction characteristics, and mixing the received tone signal and the tone signal corrected by the filter at a given ratio on the basis of tone volume control information used to control a tone volume of the tone to be generated, and outputting the mixed signal.
According to another feature of the tone volume control method of the present invention, upon mixing the received tone signal and the tone signal corrected by the filter at the given ratio on the basis of the coefficient, a tone volume balance of tones to be generated based on the received tone signal and the tone signal corrected by the filter is adjusted, and the tone volume of the tones to be generated is adjusted on the basis of the coefficient.
According to the present invention with the above arrangement, since the received tone signal and the tone signal which is corrected by the filter according to the hearing correction characteristics are mixed at a given ratio on the basis of tone volume control information that controls the tone volume, and the mixed signal is output, a tone signal to which frequency characteristics that correct the hearing characteristics are given can be generated and output in accordance with the tone volume of a tone to be generated.
Upon mixing the received tone signal and the tone signal which is corrected by the filter according to the hearing correction characteristics, when the tone volume balance of tones to be generated and the tone volume are separately adjusted on the basis of the received tone signal and the corrected tone signal, they can be independently adjusted, and a tone signal to which frequency characteristics that correct the hearing characteristics are given can be easily generated and output in accordance with the tone volume of a tone to be generated.